1. Field of the Invention
The present invention relates to a casing of a capsule endoscope, a capsule endoscope kit, an assembly method of the capsule endoscope kit, and an assembly device of the capsule endoscope kit.
2. Description of the Related Art
Conventionally, in the field of endoscopes, capsule endoscopes in which an imaging function and a wireless communication function are incorporated into a capsule-shaped casing having such a size that the casing can be inserted into the digestive tract of a subject such as a patient have been developed. A capsule endoscope moves through the inside of the digestive tract according to a peristaltic motion or the like after the capsule endoscope is swallowed from the mouth of a subject. In the period in which the capsule endoscope is inserted into the digestive tract of the subject and is excreted outside the subject, the capsule endoscope sequentially acquires images (hereinafter sometimes referred to as in-vivo images) of the inside of the organs of the subject and sequentially transmits the acquired in-vivo images to a receiving device outside the subject.
The respective in-vivo images captured by the capsule endoscope are imported to an image display device via the receiving device. The image display device displays the imported in-vivo images on a display as still images or a moving image. A user such as a doctor or a nurse observes the in-vivo images of the subject displayed on the image display device and examines the inside of the organs of the subject through observation of the respective in-vivo images.
Such a capsule endoscope needs to be sterilized and maintain the sterilized state before the capsule endoscope is used for examining a subject. Therefore, conventionally, the capsule endoscope is stored in a sterilizable casing. The casing has a configuration in which an outer casing that stores an inner casing that holds the capsule endoscope is blocked by a sterilizing sheet. A hole through which an end of the capsule endoscope closer to an imaging direction is inserted along the longitudinal direction thereof is formed in the inner casing. The inner diameter of this hole is set to be slightly larger than the outer diameter of the capsule endoscope, and multiple projections are formed on the side surface of the hole. In the inner casing, the projections abut on an area of a hemispheric portion at an end portion of the capsule endoscope, which is located outside the viewing angle of an imaging optical system and located closer to a cylindrical portion, so that the capsule endoscope is fixed so as not to move in a lateral direction. Further, step portions that are provided in the inner side of the hole, have a diameter slightly smaller than the outer diameter of the capsule endoscope, and abut on an area of the hemispheric portion of the capsule endoscope over the entire circumference, located outside the optical viewing angle abuts on the capsule endoscope so that the capsule endoscope is fixed so as not to move in a longitudinal direction. In this manner, the inner casing stably holds the capsule endoscope within the hole.
In recent years, in order to image the inside of the organs of a subject with a wide viewing angle, a capsule endoscope in which a portion of the cylindrical portion as well as the hemispheric portion of the capsule-shaped casing are formed from a transparent material to increase the viewing angle of the imaging optical system has been proposed (see Japanese Patent Application Laid-open No. 2006-288541).